.net课程设计：ZCMU通讯录（待更新）

连接数据库：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.Data.SqlClient;
using System.Threading.Tasks;

namespace Tonxunlu
{
    public class publicclass
    {
        public static SqlConnection createconn()
        {
            string connStr = @\"Data source=PC-20140124HPZO\\SQLEXPRESS;User ID=sa;pwd=123456;Initial Catalog=Data Tonxunlu\";
            SqlConnection conn = new SqlConnection(connStr);
            return conn;
        }
        public static DataTable gettable(string sql)
        {
            SqlConnection conn = createconn();
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            DataTable dt = new DataTable();
            da.Fill(dt);
            return dt;
        }
        public static bool zhixingSQl(string sql)
        {
            SqlConnection conn1 = createconn();
            SqlCommand cmd = new SqlCommand(sql, conn1);
            if (conn1.State != ConnectionState.Open)
            {
                conn1.Open();
            }
            if (cmd.ExecuteNonQuery() > 0)
            {
                return true;
            }
            else
            {
                return false;
            }
            conn1.Close();
        }
        public static bool checkUser(string userName, string passWord)
        {
            string sql = \"select 密码 from users where 用户名= \'\" + userName + \"\'\";
            DataTable dt = gettable(sql);
            if (passWord == dt.Rows[0][\"密码\"].ToString().Trim())
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}